Effects of equivalence ratio and gap size on the propagation behavior of detonations

To explore the feasibility of micro-scale pulse detonation engine propulsion system,detonation limits in narrow channels have been investigated.By observing and measuring the propagation behavior of premixed hydrogen-oxygen detonation flames in narrow gaps,effects of gap size and equivalence ratio on detonation wave pressure and velocity were experimentally analyzed.Outside the detonation limit,the detonation wave coming from the guide section can reach a steady state in the gap by self-adjustment of the pressure and velocity.The distance required by the adjustment process was growing when the gap size decreased.According to the definition of velocity deficit,the characteristics of the velocities of shock and flame front along the micro-channel were summarized,and four propagation models-steady detonation,sub-steady detonation,low-speed detonation and non-detonation were observed.